This invention relates to a resectoscope in which high frequency current leakage caused by a water drop between an electrode and a guide pipe is prevented by inhibiting the water drop from being deposited.
Recently extensive use has been made of an endoscope in which a body cavity interior can be observed and a curing treatment can be made by using an instrument in the endoscope without requiring an incision into the body. This is done by inserting an elongated insertable part into the body cavity. An example of the above-mentioned endoscope, is shown in U.S. Pat. No. 4,149,538, which discloses a resectoscope which can be inserted through a urethra to resect a swollen prostate or the like.
The above-mentioned resectoscope has a sheath body having an elongated sheath which is inserted into a urethra, a handle having a slider removably fitted into the rear end of the sheath body and an optical sighting tube for observation which is removably fitted from the rear end of the handle. An electrode device for resecting a prostate is inserted through the sheath and is fixed at the rear end to the slider so that, by operating the slider, the top of the electrode device projects out of or is retracted into the front end of the sheath.
FIG. 9 shows a slider of a resectoscope of such a device. FIG. 9(a) is an elevation of the slider and FIG. 9(b) is a sectioned view of the slider.
As shown in the drawings, the slider 1 is provided longitudinally with a guide pipe hole 3 through which a guide pipe 2 which is also a slider guide is to be inserted. An electrode inserting hole 4 is provided on the front surface of the slider parallel with the guide pipe hole 3. A water-tight O-ring 5 and an O-ring pressing member 6 are fitted into the inlet portion of the electrode inserting hole 4. A guide member 7 for guiding an electrode fixing member (not shown) is positioned and fixed in the deep portion of the electrode inserting hole 4. In this example, the slider 1 has a flat front surface.
FIG. 10 shows a slider of a resectoscope of another related example. FIG. 10(a) is an elevation of the slider and FIG. 10(b) is a sectioned view of the slider.
As shown in the drawings, a linear step 8 projects forward on the guide pipe hole 3 side and is positioned between the guide pipe hole 3 and electrode inserting hole 4 on the front surface of the slider 1. Thus, when the slider 1 is moved forward, the electrode inserting hole 4 is not in close contact with the rear end of the sheath connecting member of a resecting handle.
In a conventional resectoscope, as shown in FIG. 11, a water drop 11 is likely to be deposited so as to electrically connect the guide pipe 2 and an electrode device 10 in the part enclosed with the guide pipe 2 or the linear step 8. The electrode 10 is inserted in the electrode inserting hole 4 in the front surface of the slider 1. Therefore, there has been a problem in that high frequency current is likely to leak into the guide pipe 2 from the electrode inserting hole 4 through the water drop 11.